1. Field of the Invention
The invention relates to a method of displaying field videos, and in particular to a method of smoothly displaying field videos in an interlaced display regardless of being at a top or bottom scanning timing of a TV scanning timing and regardless of inserting or skipping a field right after any one displayed field, thereby preventing a TV screen from jitters.
2. Brief Description of the Related Art
In line with a great progress in science technologies, computers have gradually become indispensable in our daily life. By the use of computers, global information can be rapidly obtained through Internet in advance for businesses. In these years, with the great development of Internet, the amount of information transmitted through computers is increasingly getting large. In addition to text data, it further includes various audio and video data. Multimedia applications with a great amount of audio/video data have become popular in personal computers. Although data can be grabbed through Internet from far remote places, the data transmission is often being in a jam condition due to a great unusual amount of data. In this case. data can not be sequentially received as expected, causing that video and sound is not able to be displayed synchronously, resulting in a poor communication quality. On the other hand, if a receiving terminal has a different timing to a transmitting terminal, the same problem is also encountered. Consequently, how to display video, sound and other types of data synchronously becomes a key issue today.
It is well-known that multimedia signals include video, sound and other types of data signals. A simple way to avoid audio/video signals from being displayed asynchronously is to use the same network signal line for transmission. As such, multimedia signals, such as MPEG signals, can be received synchronously.
However, when restoring an interlaced video source with videos synchronous with sounds, traditional frame skip/insert is no longer suitable. When video and sound is transmitted in a synchronous way, it is necessary to have field skip/repeat. For instance, after inserting/skipping a field, the field polarities of a video source and a TV are inverted until next inserting/skipping operation.
Referring to FIGS. 1A, 1B, schematic views illustrating a traditional method of scanning videos in a normal condition and a field inserted condition, respectively, are shown.
As shown in FIG. 1A, the sequence of a TV scan timing is T, B, T, B . . . , and the sequence of field number is 1T, 1TB, 2T, 2B . . . , wherein T designates top and B designates bottom. As can be obviously known, when the TV scan timing is at a top scan timing, a top field video is displayed on the TV screen. Similarly, when the TV scan timing is at a bottom scan timing, a bottom field video is displayed on the TV screen.
Referring to FIG. 1B, it is assumed that a second field 2T is repeatedly inserted right after a first field 2T is displayed. At this moment, the second field 2T is displayed at a bottom scan timing (B), causing a down jitter on the TV screen. Subsequently, a field 2B is displayed at a top scan timing (T), and a field 3T is displayed at a bottom scan timing (B). As a result, flickers on the TV screen arc created due to opposite polarities.
In the case that a subsequent field is skipped right after any displayed field, a similar flicker on the TV screen is also created. Whether a field is inserted or skipped, the problem of flickers generated on the TV screen can not be resolved until another field is inserted or skipped latter.
In view of the above, the invention is to provide a method of smoothly displaying field videos in an interlaced display. The method of smoothly displaying field videos includes the following steps. First, a top field video is previously displayed at a top scan timing. Next, the top field video is converted into a bottom field video by transform equations. After that, the bottom field video is displayed at a bottom scan timing. The transform equations are given as follows:
L(1)=xcex1xc3x97L(2)+(1xe2x88x92xcex1)xc3x97L(1)
L(2)=xcex1xc3x97L(3)+(1xe2x88x92xcex1)xc3x97L(2)
L(3)=xcex1xc3x97L(4)+(1xe2x88x92xcex1)xc3x97L(3)
xe2x80x83L(n)=xcex1xc3x97L(n+1)+(1xe2x88x92xcex1)xc3x97L(n)
Wherein L(1), L(2) . . . , L(n) each represents a scan line of a top field video, and xcex1xc3x97L(2)+(1xe2x88x92xcex1)xc3x97L(1)xcx9cxcex1xc3x97L(n+L)+(1xe2x88x92xcex1)xc3x97L(n) each indicates a scan line of a bottom field video , respectively, where xcex1 is an interpolation weighting value with the range of 0 to 1 (i.e., 0 less than xcex1 less than 1). Preferably, the interpolation weighting value xcex1 is equal to xe2x85x9 or {fraction (1/16)} with which a better vision quality can be attained.
Furthermore, the invention is to provide another method of smoothly displaying field videos in an interlaced display. The method of smoothly displaying field videos includes the following steps. First, a bottom field video is previously displayed at a bottom scan timing. Next, the bottom field video is converted into a top field video by transform equations. After that, the top field video is displayed at a top scan timing. The transform equations are given as follows:
L(1)=L(1)
L(2)=xcex1xc3x97L(1)+(1xe2x88x92xcex1)xc3x97L(2)
L(3)=xcex1xc3x97L(2)+(1xe2x88x92xcex1)xc3x97L(3)
L(n)=xcex1xc3x97L(nxe2x88x921)+(1xe2x88x92xcex1)xc3x97L(n)
Wherein L(1), L(2), . . . L(n) each represents a scan line of a top field video, and L(1), xcex1xc3x97L(1)+(1xe2x88x92xcex1)xc3x97L(2)xcx9cxcex1xc3x97L(nxe2x88x921)+(1xe2x88x92xcex1)xc3x97L(n) each indicates a scan line of a bottom field video where xcex1 is an interpolation weighting value with the range of 0 to 1 (i.e., 0 less than xcex1 less than 1). Preferably, the interpolation weighting value a is equal to xe2x85x9 or {fraction (1/16)} with which a better vision quality can be attained.
In a method of smoothly displaying field videos in an interlaced display according to the invention, field videos can be smoothly displayed regardless of being at a top or bottom scanning timing of a TV scanning timing and regardless of inserting or skipping a field right after any one displayed field, thereby preventing a TV screen from jitters.